(1) Field of the Invention
The present invention relates to a tool designed to facilitate the extraction of a printed circuit card from a holder.
(2) Description of the Prior Art
Today, printed circuit cards are frequently assembled in a holder rack having the shape of an open topped box whose side walls form tracks for the guidance of cards sent to and out of their assembled position. Etched terminal tabs on a base strip or block of each board fit into a socket having co-acting contacts to complete a connection to an external backplane circuit. In practice, the track (forming side walls may be horizontally disposed, with the contact bearing sockets arranged on the upright rear wall.
The extraction of such printed circuit cards from their holder is a somewhat delicate operation since the abrupt reduction of frictional resistance upon disengagement of the connectors may lead to an accelerated withdrawal motion deviating from the straight linearity and thus impose bending stresses which could damage the printed circuits. This problem is perceptively increased as the printed circuit boards become larger which substantially increase the extraction force required.
Accordingly, a tool is usually required to properly extract these boards. The tool must be compact, simple to operate as well as human engineered to be comfortably operated by either hand. Many cards presently on the market have extraction mechanisms built on the printed circuit cards. This approach increases the individual card cost and therefore a separate tool is a more economical approach to the card removal requirement.
It therefore becomes an object of the present invention to provide an improved tool of the character described which facilitates the extraction of such printed circuit cards.